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Risk of dissociation rare, but significantly higher with large-diameter glenospheres
When larger-diameter glenospheres were implanted, there was a significantly higher likelihood of glenosphere dissociation after reverse shoulder arthroplasty, according to study results.
Reviewing a reverse shoulder arthroplasty database, researchers identified patients with glenosphere dissociation that occurred between 1999 and 2013, noting prosthesis type, glenosphere size and factors contributing to dissociation. The researchers documented evidence of wear or corrosion on the Morse taper in five retrieved implants and biomechanically investigated improper Morse taper engagement.
Results revealed 13 patients with glenosphere dissociation, with a glenosphere size distribution of 32 mm in one patient, 36 mm in four patients, 40 mm in six patients and 44 mm in two patients. The researchers found a correlation between incidence of dissociation to glenosphere size. With regard to taper damage, the researchers found damage was limited to fretting wear, and minimal evidence of taper corrosion was observed.
According to study results, torsional capacity of the glenosphere-baseplate interface was reduced by 60% through biomechanically, improper taper engagement. – by Casey Tingle
Disclosures: Cusick reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.